Transistorized oscillatory system



April 2 1961 E. A. FERNBACH 2,981,865

TRANSISTORIZED OSCILLATORY SYSTEM Filed June 8, 1959 2 Sheets-Sheet 1iia- INVENTOR. fizz/1'77 A, WerWZJa Z,

United States Patent 2,981,865 TRANSISTORIZED OSCILLATORY SYSTEM FiledJune 8, 1959, Ser. No. 818,637 18 Claims. (Cl. 315-206 This inventionrelates to transiston'zed oscillatory systems and more particularly totransistor blocking oscillators suitable for producing high voltages,and to voltage supply and automotive ignition systems embodyingtransistor blocking oscillators.

An object of this invention is to improve automatic ignition systems.

Another object of this invention is' to increase the transfer of energyfrom a transistor blocking oscillator circuit to an output device.

Another object of this invention is to increase the output of atransistor blocking oscillator without overheating the transistor.

Another object of this invention is to establish im-' provedelectrostatic shielding between a collector transformer winding in atransistor blocking oscillator and the high voltage transformer winding.

A feature of this invention is an improved automotive ignition system inwhich a plurality of abrupt high amplitude voltage spikes are appliedtoeach spark plug at each ignition thereof through the use of a transistorblocking oscillator circuit.

Another feature of this invention is a transistor blocking oscillatorcircuit in which the collector is coupled both to the base and to theemitter. 7

Another feature of this invention is the provision of a transformerwinding for the emitter of a vtransistor in a blocking oscillatorcircuit both to couple the emitter to the collector and toelectrostatically shield the collector winding from the output highvoltage winding of the transformer.

Another feature of this invention is the provision of a creasing thebase drive in a transistor blocking oscillator and for fusing the basecircuit of the transistor.

Another feature of this invention'is an improved igni-' tion system.including a transistor blocking oscillator and a pulse generator.

The manner of accomplishing the foregoing objects and the detailednature of the foregoing features, and other objects and features of theinvention, will become apparent from the following detailed descriptionof embodiments of the invention when read with reference to theaccompanying drawings in which:

' Fig. l is a schematic representation of an ignition system embodyingcertain of the principles of the present invention;

. Fig. 2 is a schematic representation of modification of the ignitionsystem of Fig. 1;

Fig. 3 is a schematic representation of a blocking oscillator type ofhigh voltage supply;

Fig. 4 is a fragmentary schematic representation of a modification ofthe circuitry of Fig. 3;

Fig. 5 is a schematic representation of a pulse generating systemsuitable for use as a part of an ignition system; 1

Fig. 6 is a diagram of certain time-versus-voltage relations existing,for example, in the circuits of Figs. 1, and 2; and

ice

Fig. 7 is a schematic representation of a system for producing a highdirect voltage and embodying certain principles of the invention. 7

The ignition system of Fig. 2 is intended to supply timed bursts ofenergy to each of a plurality of spark plugs, such as spark plug 10, ina predetermined sequence, the sequential distribution to the spark plugsbeing accomplished by means of a distributor 12, and the timing beingaccomplished by means of an interrupter 14, distributor 12 andinterrupter 14 being operated in synchronized relationship as by beingmechanically driven by common rotating means synchronized with theengine. In practice, for example, the distributor 12 and the interrupter14 may take the form of the conventional distributor and contacts inmodern automobiles modified only in the removal of the capacitor whichnormally shunts the each successive spark plug is fired. Each suchclosure of the contacts results in a burst of high voltage pulses beingapplied through the distributor to the appropriate one of the sparkplugs. The contacts of interrupter 14 then open and the distributoradvances to establish a' connection to the next succeeding spark plug inthe sequence, whereupon, at the appropriate time, the contacts of in-.terrupter 14 again close to apply a burst of pulses to that spark plug,and so on through the sequence.

The closure of the contacts of interrupter 14 initiates the operation ofa type of blocking oscillator circuit including a transistor 16 (hereinassumed to be a p.n.p. transistor) and a transformer 18 having aplurality of magnetically linked windings 20, 22, 24, 26, 23 and 30. Thesystem is energized from a source of directvoltage 32 which may, forexample, be a twelve-volt automobile battery.

The base of the transistor 16 is connected through winding 20, resistor34, variable resistor 36, and interrupter 14 to the negative terminal ofsource 32, and the base is also connected to one terminal of capacitor38 to the positive terminal of source 32. The collector of transistor 16is connectedthrough Winding 16 and variable resistor 40 to the negativeterminal of source 32. The emitter of transistor 16 is connected'throughwinding 24 and variable resistor 42 to the positive terminal of source32. A capacitor .44 is connected fromthe junction of winding 22 andresistor 40 to the emitter of transistor such as spark plug 10 and theother terminal, which is grounded.

When the contacts of interrupter 14 close, transistor 14 becomesconductive, the emitter current flowingthrough winding 24, the collectorcurrent flowing through Winding 22, and the base current flowing throughwinding 20. The primary blocking oscillator coupling is between thecollector and the base circuits (with a common emitter) by means oftransformer windings 22 and 20. The collector current in winding 22induces a cur- 5 rent in and a voltage across winding 20 which is in adirection (negative in the assumed case) to increase the base drive andto increase the flow of collector current.- The increased collectorcurrent through winding 22 fur ther increases the base drive, and thisregenerative action continues until saturation is reached and no morecollecmenses t. tor current increase occurs. When this condition isreached, the collector current begins to diminish, which reduces thebase drive to further reduce the collector current, and so forth in aregenerative sense until the transistor is at cut'off, that is, thecollector current is substan tially zero. Thereafter, the cycle ofincreasing and decreasing conduction is repeated.

The rate of reduction of collector current is high and,

the resultant rapid collapse of flux in the collector winding 22 inducesa high voltage in secondaries 23 and 30, which is applied to the sparkplugs.

A representation of an oscillograph of the output voltage of the systemis illustrated in Fig. 6 of the drawings. The initial pulse is ofrelatively long duration and of negative polarity, but thereafter aplurality of high-frequency, high amplitude voltage spikes are appliedacross the spark gap to produce ignition of the combustible mixture inthe cylinder.

The frequency of the spikes is determined primarily by thecharacteristics of the transformer 18 and preferably a high qualitygrain-oriented, high permeability core should be employed. Desirably,the frequency is in the order of six kilocycles per second to fortykilocycles per second, allowing in the order of eight to thirty-twofiring pulses per spark plug per sequence instead of the conventionalsingle pulse.

The number of pulses per burst may be determined solely by the period ofclosure of the contacts of interrupter 14 if desired, or the terminationof the oscillation may be achieved by selecting the system parameters toproduce self blocking after a preselected number of cycles. However, inview of the magnitude of the energy requirements of the spark plugs,either a relatively expensive power transistor must be employed or thetime duration of operation of the transistor for each pulse burst mustbe limited. If the interrupter contacts control the duration ofoscillation, the oscillatory period at low engine speeds is relativelylong so that the outputof the system must be reduced to preventoverheating or destruction of the transistor, and this adversely affectsthe operation of the system at high engine speeds when the duration ofthe pulse bursts is short and when losses in the transfer of energy tendto be more serious. Accordingly, it is preferred that the closure timeof the interrupter contacts control the duration of the pulse burst athigh engine speeds and that the self blocking of the circuit terminatethe oscillatory action at low engine speeds. This arrangement has thefurther advantage that the transistor will not oscillate for adestructive period if, while the interrupter contacts are closed, theautomobiles ignition switch is turned on but the engine is not started.

The circuit of Fig. 1 also includes means for permitting the transfer ofadequate energy to the output without excessive heating of thetransistor, that is, meansfor increasing the current in secondaries 28and 30 without increasing the base current to the point of destructionof the transistor, and, in fact, without any increase in the basecurrent. This means includes emitter Winding 24. Winding 24 is wound andconnected so that the emitter current, at any instant, will result inthe induction of a voltage across those windings 28 and 30 in adirection to aid or increase the voltage developed across those windingsas a result of the flow collector current through winding 22 at thatinstant. In a practical embodiment of the unit the addition of winding24 resulted in a doubling of the current and doubling of the output highvoltage without changing the base current. In this way, a transistordesigned to provide, for example, thirty-five times currentamplification will handle currents as much as seventy times the basecurrent without effectively increasing the function temperature. In apractical embodiment, at base currents of 30 milliamperes, thecollectorand emitter currents were 1.5 amperes and 1.53 amperes, respectively,while at a base current of 100 milliamperes, those values were 2.00amperes and 2.20 amperes, respectively. It will be noted that if, inlieu of providing emitter winding 24, an effort is made to increase theoutput voltage by increasing the turns of winding 22, the effectiveinductance of winding 22 will increase to the point where operation ofthe equipment is adversely affected since it affects the impedance ofthe collector circuit and the collector to base coupling.

The provision of winding 24 has another significant advantage. Byphysically disposing winding 24 between winding 22 and winding 28-30,winding 24 serves as an electrostatic shield between the high voltagewindings and the collector winding to avoid electrostatic interactionwhich would be harmful to the collector.

The provision of an emitter winding is, of course, not imperative to thepractise of all of the principles of the invention, and Fig. 3illustrates a blocking oscillator circuit with transformer-coupledcollector and base and common emitter which does not utilize an emitterwinding. In that circuit, the collector of transistor 50 is con, nectedto the negative terminal of source 52 via winding 54 of transformer 56and resistor 58, the base is connected to that terminal via winding 60,resistor 62, variable resistor 64 and the contacts of interrupter 66,and the emitter is connected to the positive terminal of source 52solely through resistor 68. Capacitor 70 is connected from the junctionof resistor 58 and winding 54 to the positive terminal of source 52,while capacitor 72 is connected from the junction of resistor 62 andwinding 69 to that positive terminal. While the output is taken acrosssecondary winding 74 in the circuit of Fig. 3, it will be appreciatedthat an auto-transformer feature can be incorporated by connecting oneend of the secondary winding to a tap on the collector winding, as isillustrated in the fragmentary showing of Fig. 4 in which correspondingparts have been given corresponding reference characters, with theaddition of a prime.

Fig. 2 of the drawings illlustrates a modification of the Fig. lcircuitry to establish a primary blocking oscillator transformercoupling between the emitter and the collector, with no such transformercoupling between the collector and the base. In that circuit, thecollector of transistor is connected to the negative terminal of source82 through winding 84 of transformer 86 and through resistor 88, and thebase is connected to that terminal through resistors 90 and 92 andinterrupter 94. Capacitor 96 is connected between the base and thepositive terminal of source 82. The emitter of transistor 89 isconnected through winding 98 of transformer 86 and resistor 100 to thepositive terminal of source 82, and capacitor 102 is connected from thejunction of resistor 88 and winding 84 to the emitter. Pulse winding 104may also be provided, and the output is taken across series aidingsecondaries 106 and 108, that output voltage being applied throughdistributor 110 and across, for example. spark plug 112. i

In the circuit of Fig. 2, the current build up to saturation andreduction to effective cut-off occurs as a result of thecollector-emitter transformer coupling, and that same coupling resultsin the production of a greater output voltage and can result inelectrostatic shielding of the col- The use of a resistor of this typenot only advantageously,

controls the base drive of the transistor to insure adequate drive ofthey base but also can be employed to fuse the; base circuit byselecting a lamp having a current carrying;

capability (to the point of rupture of the filament) less than themaximum current carrying capability of the base circuit.

It will be appreciated that the initiation of conductivity 1 of thetransistor can be accomplished by means other than the conventionalautomotive breaker points,including means for varying the impedance ofthe control circuit 1 riphery. Cooperating with element 120 is anincomplete toroidal core 124, both elements 120 and 124 being formed,for example, of soft iron. The resultant magnetic circuit has areluctance which is less when two of the protuberances on rotor 120 arealigned with the tips of core 124 than otherwise. upon core 124. One endof coil 126 is connected through winding 128 of transformer 130 to thejunction between resistor 132 and transformer winding 134, the other endof resistor 132 being connected to the negative terminal of source 136,and the other end of winding 134 being connectedto the collector oftransistor 138. The other end of coil 126 is connected to the base oftransistor 138 through resistor 140. The center tap of coil 126 isconnected to the positive terminal of source 136.

The emitter of transistor 138 is connected through Winding 142 oftransformer 130 and through resistor 144 to the positive terminal ofsource 136. Again, the output is taken across series aiding secondaries146 and 148, and an auxiliary pulse may be derived by winding 150 andapplied between terminals 152 to initiate the performance of anauxiliary function. v g

It will be perceived that the system of Fig. 5 acts as a collector-basecoupled oscillator with variable coupling. When the teeth orprotuberances on rotor 120 are out of.

alignment withthe core 124, the degree of coupling is insufficient toproduce regeneration When the teeth become aligned with the core, theflow of collector current in winding 134 will induce a current inwinding 128 which will flow through the upper half of winding 126 inview of the series interconnection of that winding half and winding 128.The flow of current through the upper half of winding 126 will, due tothe close coupling of the two halves of winding 126 with the coremagnetic circuit in a low-reluctance state, induce a voltage. across thelower half ofwinding 126 of a polarity tending to drive the basenegative (assuming a pup transistor), which is a regenerative couplingaction. This action results in current increase to saturation, followedby current decrease to cutoff, and so on. a e

The circuit of Fig. 7 illustrates the applicability of the principles ofthe present invention to the derivation of a high-amplitude directvoltage for use in, for example, television receivers. In that circuit,the collector of transistor 156 is connected directly to the nega-' tiveterminal of source 158 (which is here assumed to have a higher voltagethan in the other described circuits, as, for example, 45 volts) throughWinding 160 of transformer 162, the base of transistor 156 is connectedthrough winding 164 of transformer 162 and through a network comprisingvariable resistor 1 66 and capacitor 168 to the positive terminal ofsource 158, and the emitter is connected through windings 170 and 172oftransformer 162 to the positive terminal (ground) of source 158. Thesynchronizing pulses (sync. output) are applied through capacitor 174,one terminal of which is connected to the base of transistor 156, andthe gating pulses are applied through capacitor 176, one terminal of A-center-tapped coil 126 is wound which isconnected to the junction ofwindings 170 and 172 of transformer 162.

The synchronizing pulses are applied through capacitor 174 to the baseto initiate conductivity of the transistor. An increase in the collectorcircuit through winding 160 induces a voltage across winding 164 of apolarity tending to drive the base in a direction to increase theconduc-' tivity, and this regenerative action continues to saturationand thence to cut-ofi. The gating pulses output is taken across winding172. e

The oscillatory output, as it appears across secondary winding 17 8 oftransformer 162 is rectified and filtered in the normal fashion toproduce an output direct voltage between conductors 180 and 182 forapplication, for example, to the high voltage electrodes of thekinescope.

Other utilization of the principles of this invention will be apparentto those skilled in the art. apparent that the embodiments of theinvention herein disclosed are well calculated to fulfill the objects ofthe.

means for "applying a burst of high frequency voltage spikes to each ofsaid spark plugs in a predetermined sequence comprising a transformerhaving a primary and a secondary winding, generating means effective'inre-' sponse to each triggering signal applied thereto to apply tosaid primarywinding a plurality of generally saw-tooth pulses eachhaving a rise time which is long relative to.

the fall time thereof, signal means driven by the rotating means forapplying a plurality of triggering signals to said generating means, anddistributing means driven by said rotating means for connecting saidsecondary winding to said spark plugs in a preselected sequence.

2. In an automotive ignition system including rotating means driven bythe engine and a plurality of spark plugs, means for applying a burst ofhigh frequency voltage spikes to each of said spark plugs in apredetermined sequence comprising a transformer having a primary and asecondary winding, transistor blocking oscillator circuit meanseffective in response to each triggering signal applied thereto to applyto said primary winding a plurality of generally saw-tooth'pulses eachhaving a rise'time which is'long relative to the fall time thereof,

signal means driven by the rotating means for applying a plurality oftriggering signals to said generating means, and distributing meansdriven by said rotating means for plugs, means for applying a burst'ofhigh frequency voltage spikes to each of said spark plugs in apredetermined sequence comprising transistor blocking oscillator meanselfective'in response to each short duration triggering signal appliedthereto to oscillate for a preselected period following the terminationof said signal and to produce a plurality of generally saw-tooth pulseseach having a'rise time which is long relative to the fall time thereof,said transistor blocking oscillator means comprising a transformerhaving a secondary Winding and a first primary winding, a transistorhaving an emitter, a collector and a base, means connecting saidcollector in series with said first primary winding, means includingsaid first primary winding and an additional winding on said transformerconnected in series with said base and magnetically coupled to saidfirst primary winding for coupling said collectorto said base to provideblocking oscillator action, and means for increasing the current in saidsecondary. winding without substantially increasing the base cur- Whileit will be or fairmeaning of the sub-' rent comprising a second primarywinding for said transformer connected in series with said emitter,signal means driven by the rotating means for applying a plurality ofshort duration triggering signals to said transistor blocking oscillatormeans, and distributing means driven by said rotating means forconnecting said secondary winding to said spark plugs in a preselectedsequence, said signal means applying a triggering signal to saidtransistor blocking oscillator means each time that said secondarywinding is connected to a spark plug.

4. The combination of claim 2 in which the duration of each burst ofhigh frequency votlage spikes and the number of generally saw-toothpulses which are generated in response to each triggering signal isefiectively independent of the duration of the individual triggeringsignals and eifectively independent of the duration of the intervalbetween triggering.

5. The combination of claim 2 in which the duration of each burst ofhigh frequency voltage spikes at relatively high engine speeds iscontrolled by said signal means and in which the duration of each burstof high frequency voltage spikes at relatively low engine speeds iscontorlled by the blocking action of said blocking oscillator means.

6. The combination of claim 2 inwhich the duration of each of saidbursts of high frequency voltage spikes is effectively constant over asubstantail range of relatively low engine speeds and in which theduration of each of said bursts of high frequency voltage spikes variesinversely with engine speed over a range of. relatively high enginespeeds.

7. In an automotive ignition system including rotating means driven bythe engine and a plurality of spark plugs, means for applying a burst ofhigh frequency voltage spikes to each of said spark plugs in apredetermined sequence comprising a transformer having primary,secondary and tertiary windings, transistor blocking oscillator meansincluding a transistor and said primary and tertiary windings effectivein response to each triggering signal applied thereto to apply to saidprimary winding a plurality of generally saw-tooth pulses each having arise time which is long relative to the fall time thereof, signal meansdriven by the rotating means for applying a plurality of triggeringsignals to said generating means, and distributing means driven by saidrotating means for connecting said secondary winding to said spark plugsin a preslected sequence.

8. In an automotive ignition system including rotating means driven bythe engine and a plurality of spark plugs, means for applying a burst ofhighfrequency voltage spikes to each of said spark plugs in apredetermined sequence comprising a transformer having primary,secondary and tertiary windings, transistor blocking oscillator meansincluding a transistor and said primary and tertiary windings effectivein response to each short duration triggering signal applied thereto tooscillate for a'preselected period following the termination of saidsignal and to apply to said primary winding a plurality of generallysaw-tooth pulses each having a rise time which is long relative to thefall time thereof, signal means driven by the rotating means forapplying a plurality of short duration triggering signals to saidtransistor blocking oscillator means, and distributing means driven bysaid rotating means for connecting said secondary winding to said sparkplugs in a preselected sequence.

9. In an automotive ignition system including rotating means driven bythe engine and a plurality of spark plugs, means for applying a burst ofhigh frequency voltage spikes to each of said spark plugs in apredetermined sequence comprising a transformer having primary,secondary andtertiary windings, transistor blocking oscillator meansincluding a transistor and said primary and tertiary windings effectivein response to each short duration triggering signal applied thereto tooscillate for a preselected period following the termination of saidsignal and to apply to said primary winding a plurality ofgenerallysaw-tooth pulses each having a rise 7 time which-is longrelative to the fall time thereof, signal means driven by the rotatingmeans for applying a plurality of short duration triggering signals tosaid transistor blocking oscillator means, and distributingrneans drivenby said rotating means for connecting said secondary winding to saidspark plugs in a preselected sequence, said signal means applying atriggering signal to said transistor blocking oscillator means each timethat said secondary winding is connected to a spark plug.

10. The combination of claim 9 in which said primary Winding isconnected in series with said collector and said tertiary winding isconnected in series with said base so that said collector istransformer-coupled to said base.

11. The combination of claim 10 further including an additional windingon said transformer connected in series with said emitter.

12. The combination of claim 10 further including additional windingmeans on said transformer connected in series with said emitter andphysically disposed between said primary and said secondary windings forelectrostatically shielding said primary winding from said secondarywinding.

13. The combination of claim 9 in which said primary winding isconnected in series with said collector and said tertiary winding isconnected in series with said emitter so that said collector istransformer-coupled to said, emitter. v

14. In an automotive ignition system including rotating means driven bythe engine and a plurality of spark plugs, means for applying a burst ofhigh frequency voltage spikes to each of said spark plugs in apredetermined sequence comprising a transformer having a first and asecond primary winding and a secondary winding, transistor blockingoscillator circuit means effective in response to each short durationtriggering signal applied thereto to oscillate for a preselected periodfollowing the termination of said signal and to apply to said primarywinding a plurality of generally. saw-tooth pulses each having a risetime which is long relative to the fall time thereof, signal meansdriven by the rotating means for applying a plurality of short durationtriggering signals to said transistor blocking oscillator means, anddistributing means driven by said rotating means, for connecting saidsecondary winding to said spark plugs in a preselected sequence, saidsignal means applying a triggering signal to said transistor blockingoscillator means each time that said secondary winding is connected'toany spark plug, said transistor blocking oscillator means comprising atransistor having an emitter, a collector and a base, means connectingsaid first primary winding in series with said collector, and meansconnecting said second primary winding in series with said emitter.

15. The combination of claim 14 in which said second primary winding isphysically disposed between said first primary winding and saidsecondary winding for electrostatically shielding said primary from saidsecondary winding.

16. In an automotive ignition system including rotating means driven bythe engine and a plurality of spark plugs, means for applying a burst ofhigh frequency voltage spikes to each of said spark plugs in apredetermined sequence comprising a transformer having first and secondprimary windings and a secondary winding, a transistor having anemitter, a collector and a base, a pulse generator comprising a tappedcoil disposed upon a magnetic circuit element and means driven by saidrotating means for periodically varying the reluctance of said magneticcircuit, a source of potential having first and second terminals, meansconnecting the tap of said coil to said second terminal, meansconnecting said base to one end of said coil, a resistor, meansconnecting said first primary winding and said resistor in seriesbetween said collector and said first terminal, means connecting saidsecond primary winding from the junction of said first primary windingand said resistor to the other end of said coil, and means forconnecting said emitter to said second terminal.

17. In an automotive ignition system including rotating means driven bythe engine and a plurality of spark plugs, means for applying a burst ofhigh frequency voltage spikes to each of said spark plugs in apredetermined sequence comprising a transformer having first, second andthird primary windings and a secondary winding, a transistor having anemitter, a collector and a base, a pulse generator comprising a tappedcoil disposed upon a magnetic circuit element and means driven by saidrotating means for periodically varying the reluctance of said magneticcircuit, a source of potential having first and second terminals, meansconnecting the tap of said coil to said second terminal, meansconnecting said base to one end of said coil) a resistor, meansconnecting said first primary winding and said resistor in seriesbetween said collector and said first terminal, means connecting saidsecond primary Winding from the junction of said first primary windingand said resistor to the other end of said coil, and means includingsaid third primary winding for connecting said emitter to said secondterminal.

18. In an automotive ignition system including rotating means driven bythe engine and a plurality of spark plugs, means for applying a burst ofhigh frequency voltage spikes to each of said spark plugs in apredetermined sequence comprising transistor blocking oscillator circuitmeans effective in response to each triggering signal ap- 10 pliedthereto to produce a plurality of generally sawtooth pulses each havinga rise time which is long relative to the fall time thereof andcomprising a transformer having a secondary winding and a first primaryWinding, a transistor having an emitter, a collector, and a base, meansconnecting said collector in series with said first primary winding,means including said first primary winding for coupling said collectorto said base to provide blocking oscillator action, and means forincreasing the current in saidsecondary Winding without substantiallyincreasing the base current comprising a second 'primary Winding forsaid transformer connected in References Cited in the file of thispatent UNITED STATES PATENTS 1,589,489 Snook June 22, 1926 1,968,930Cotter et al. Aug. 7, 1934 2,347,286 Sandretto Apr. 25, 1944 2,475,995Short July 12, 1949 2,780,767 ,Janssen Feb. 5, 1957 2,816,230 LindsayDec. 10, 1957 2,849,615 Gustafson Aug. 26, 1958 2,878,298 GiacolettoMar. 17, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 2,981,;865 April 25, 1961 I Erwin A. Fernbach It is herebycertified that error appears in the above numbered patent requiringcorrection and that the said Letters Patentv should read as correctedbelow.

Column l line 20, for "automatic" read automotive line 45 for "theprovision of a" read a means for in' --g Column 3 line 63, after "flow"insert of Column 7 line 23 for"contorlled" read controlled line 27 for"substantail" read --substantial line 47, for "preslected" readpreselected Signed and sealed this 14th day of November 19 1.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of PatentsUSCOMM-DC

